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Installing a photovoltaic system: useful to know

Where can it be installed?

Photovoltaic system modules can be installed on a building's roof, its façade or on the ground.

During the initial survey, the installer will check the feasibility, taking into account:

  • the available space required for the installation of the modules (for every 1,000 W of installed power, about 3-4 photovoltaic modules are necessary)
  • the correct exposure and incline of the surface, which must be facing southwards, southeast or southwest. The incline should be between 10° and 35°
  • the absence of any obstacles that could create shade.


What authorisations are necessary for pv installation?

  • if the building upon which the system is to be installed is not situated within an area subject to planning restrictions (environmental, historical, artistic, landscape, etc.), then, in accordance with the specific requirements of the local municipal urban planning regulations, the photovoltaic system can be installed without a specific authorisation. However, installation does require prior communication to the grid operator of the "Unified application form for the construction, connection and operation of a small photovoltaic system incorporated onto the roof of a building". The form consists of two parts: the first must be completed and sent before the installation, and the second must be completed and sent once the installation has been concluded.
  • if, on the other hand, the property is located in an area subject to planning restrictions, a landscape waiver must be acquired from the relevant local authorities and an ordinary or simplified authorisation must be requested, as in the case of other building interventions.


The installer will evaluate the specific cases in order to suggest and design the most suitable installation to meet every requirement.


Does the photovoltaic system also work when levels of solar irradiation are low?

Yes, the photovoltaic modules can capture every small amount of solar irradiation and convert it into usable energy to power a home, as long as the simple rules relating to the installation – the inclination and orientation of the panels – have been followed.


What happens to my system in the event of a power failure?

If the inverter detects changes or drops in the voltage of the electricity grid, it immediately disconnects the system.


Why purchase a photovoltaic system?

There are many advantages to using a photovoltaic system; the main ones are listed below:

  1. Respect for the environment: it eliminates pollution and associated greenhouse gas emissions during the energy production cycle
  2. Cost-effectiveness: savings on energy costs thanks to self-consumption and enhancing the value of the property
  3. Reliability: a system has an average duration of 25 years, and is easy to maintain
  4. Modularity: the possibility to modify the system's power output at any time by simply varying the number of modules
  5.  Independence: ability to self-produce part of the energy consumed when the sun is shining. Furthermore, those who choose to incorporate batteries into the system can store the surplus energy produced for subsequent use when required.


Are there any incentives for installing a photovoltaic system?

The incentives granted in Italy for photovoltaic systems are:

  1. Fiscal detraction: the initial investment in purchasing a photovoltaic system can benefit from a tax deduction of 50% under the legislation for works considered building renovations
  2. Net metering: the net metering service* is a particular form of on-site self-consumption that makes it possible to offset the electricity produced and fed into the grid with that taken and consumed at a different time from when the production occurred. Net metering therefore uses the electrical system as a tool for the virtual storage of electricity produced but not contextually self-consumed. The service provided by the GSE (the electricity services operator) following the signature of a specific contract, allows the producer-owner of a photovoltaic system not exceeding 500 kW (the average residential system is 3kW) to receive compensation for the difference between the value associated with the electricity produced and fed into the grid and the value associated with the electricity taken and consumed in a different period from when production occurred. 


*Determined by Resolution 570/2012/R/efr AEEGSI


How long is the useful life of a photovoltaic system?

Photovoltaic systems last an average of 25 years .

Taking into consideration their main components:

  • the modules have a life span of 25 to 30 years, with a decline in energy performance generally below 20% at the end of this period;
  • inverters are high-tech devices that generally have a shorter life span than the modules.


Is it cost-effective to connect the photovoltaic system to the electricity grid?

Although stand alone photovoltaic systems are technically feasible, maintaining contact with the electricity grid, when present, is always cost-effective. Stand alone systems are very expensive if they are to achieve the same levels of service as a grid-connected system; moreover, they cannot benefit from net metering.

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